1. Field of the Invention
This invention relates generally to the design of electrosurgical instruments and more particularly to a monopolar or bipolar electrosurgical instrument having an extendable lumen which permits selective irrigation and aspiration of the treatment region. In one embodiment, a sheath is reciprocally moveable in relation to the main housing of the electrosurgical instrument and features at least one pressure release port at its distal end to reduce the amount of suction provided to tissue. In an alternative embodiment, a tubular housing having at least one distal electrode extending therefrom is reciprocally movable within a stationary, external sleeve.
2. Discussion of the Prior Art
Monopolar and bipolar electrosurgical instruments typically include an electrode extending from a distal end of a rigid or flexible tube. In these instruments, it is desirable to include a lumen with a distal exit port positioned near the electrodes to supply irrigation fluid and to aspirate that fluid and debris from the region. Although electrodes used on these instruments are configured for optimal contact with tissue, the fact that they generally project outwards makes it difficult to manipulate the distal end of the device to position an irrigation/aspiration port adjacent to tissue, in order to selectively flush one area of a treatment region or to aspirate blood or bodily fluids from the region. Although it is common to include a suction or irrigation lumen within such instruments, the port is often displaced too far from tissue to be optimally effective. This obstruction occurs even when the electrodes are specially dimensioned to enhance irrigation and aspiration. Furthermore, these instruments are typically inserted through the lumen of a laparoscopic trocar or endoscope, within which the protruding electrodes may be damaged as the instrument is negotiated through bends and curves in the lumen.
The present invention solves these problems presented in the prior art by providing a retractable or extendable sleeve or sheath which may be extended distally in relation to the surface holding the electrodes and which, when extended, encompasses the electrode housing and electrodes of the electrosurgical instrument. When extended, the sleeve protects the electrodes during insertion and also functions as an extension of the suction and irrigation port. Thus, when extended, the point at which suction takes place is provided closer to the actual treatment site than was possible using prior art instruments. Alternatively, the housing on which the electrodes are mounted may be retracted into a stationary sleeve, again enabling the orifice of the irrigation/aspiration tube to be effectively placed nearer a treatment region than was possible in the prior art.
It is accordingly a principal object of the present invention to provide a new and improved electrosurgical instrument for insertion into a laparoscopic trocar or endoscope.
Another object of the present invention is to provide a new and improved apparatus for irrigation and aspiration of a treatment region featuring a retractable and extendable sheath to enable application of irrigation and aspiration nearer a treatment region.
It is yet another object of the present invention to provide a new and improved apparatus for irrigation and aspiration of a treatment region featuring a retractable and extendable electrode housing which may be withdrawn into a stationary sheath to enable application of irrigation and aspiration nearer a treatment region.
A further object of the present invention is to provide a new and improved apparatus for attaining a level of controlled suction which will not damage tissue by grasping it too strongly.
A still further object of the present invention is to provide a new and improved apparatus having a sheath which acts as a protective sleeve as the instrument is inserted through a laparoscopic trocar or endoscope.